Bookshelf laden and unladen, showing camber 36 Pin connecting parts of bridge 37 Bridge rollers in section and in plan 38 Girder sections in various forms 39 Rubber cylinders solid and hollow compared in sag 40 Handle bar of bicycle in steel tubing 40 A sulky in steel tubing 41 Pneumatic hammer in steel tubing 41 Fishing rod in steel tubing 41 Bridge of steel pipe 41 Arch bridge of steel pipe 42 Spiral fire-lighter 42 Spiral weld steel tube 42 Largest stone arch in the world, Plauen, Germany 43 Church of St. Remy, Rheims, France 43 Curve of suspended chain 44 Dam across Bear Valley, California 44 Ferguson locking-bar 45 Hand-hole plates, Erie City water-tube boiler 46 Bullock cart with solid wheels 47 Ball thrust collar bearings 48 Rigid bearings for axles of automobiles 48 Hyatt helical roller bearing. Ditto supporting an axle 49 Treads and risers of stairs joined by curves 49 Corner Madison Square Garden, New York 50 Two pipes with funnel-shaped junction 50 MODEL BASIN, U. S. NAVY, WASHINGTON, D. C. _facing_ 54 Viking Ship 56 Clipper ship “Young America” 58 Steamship Kaiser Wilhelm II 60 Cargo steamer 61 U. S. Torpedo-boat destroyer 62 Cross-sections of ships 63 Racing automobile. Wedge front and spokeless wheels 66 Bilgram skew gearing 67 Grain elevator 68 Robins conveying belt 68 Ewart detachable link belting 69 Curves of turbines 70 Steel vanes of windmill 70 Pelton water wheel and jet 71